Method for producing large reinforced seamless casings and the product obtained therefrom

Abstract

A method of forming a high tensile strength, reinforced, seamless, large cylindrical casing wherein a metal such as nickel is electrodeposited in conjunction with reinforcing materials such as carbon fibers to form a matrix on the outer surface of a rubber layer, the surface of which has been rendered electroconductive, deposited on a mandrel but separated therefrom by a separating material, such as wax, which will permit ready separation of the finished casing product from the mandrel when by heating the latter until the separating material melts or liquefies.

What is claimed is: 
     
       1. A method for the electrolytic production of a filament-wound, reinforced metal casing having an internally attached insulation layer, which comprises the following sequential steps: (a) coating the outer surface of a hollow mandrel with a layer of a separating material, said mandrel having dimensions slightly smaller than length and diameter dimensions of the desired filament-wound, reinforced metal casing;   (b) coating the layer of separating material with a layer of a non-conductive insulating material;   (c) coating the layer of insulating material with a thin film of electrolytically conductive material;   (d) immersing the thus prepared mandrel in an electroplating bath provided with means for rotating said mandrel at controlled speeds, and wherein said electroplating bath contains a metal salt electrolyte solution at a depth whereby not over 25% of the outer surface of said mandrel is not immersed and remains exposed;   (e) electrodepositing metal on the thus prepared outer surface mandrel while the mandrel is being rotated through said electrolyte solution;   (f) winding reinforcement fibers on the exposed outer surface of the mandrel as the mandrel is being rotated and while electrodepositing metal from said electrolyte on to the outer surface of the mandrel to form a reinforced metal casing having an internal insulation layer attached thereto; and   (g) separating said filament-wound reinforced metal casing from the mandrel by applying heat to said mandrel whereby the separating material on the outer surface of the mandrel melts thereby permitting the reinforced metal casing with the internally attached insulating layer to be separated from the mandrel.   
     
     
       2. The method of claim 1 wherein the mandrel is constructed from a material selected from the group consisting of stainless steel, nickel, aluminum, reinforced polyester epoxy, and engineering plastics. 
     
     
       3. The method of claim 1 wherein the separating material is selected from the group consisting of wax, silicon, grease, low melting temperature metals, selectively soluble salts, and chemically decomposable plastics. 
     
     
       4. The method of claim 3 wherein the separating material is wax. 
     
     
       5. The method of claim 1 wherein the insulating material is selected from the group consisting of natural synthetic rubber, plastic composition shields, teflon, lead, and refractory materials having a flexible matrix. 
     
     
       6. The method of claim 5 wherein the insulating material is natural or synthetic rubber. 
     
     
       7. The method of claim 1 wherein the thin conductive film is composed of a material selected from the group consisting of silver, gold, copper, and electrolytically conductive material. 
     
     
       8. The method of claim 1 wherein the metal being electrodeposited on the mandrel is selected from the group consisting of nickel, chromium, copper, brass, bronze, and lead. 
     
     
       9. The method of claim 1 wherein said reinforcing filaments are selected from the group consisting of carbon fibers, glass fibers, boron fibers, and high modulus organic polymer filaments. 
     
     
       10. A method for the electrolytic production of a filament-wound reinforced nickel metal casing having an internally attached insulation layer, said casing having a long length and a large diameter which comprises the following sequential steps: (a) coating the outer surface of a hollow mandrel with a separating material, said mandrel having dimensions slightly smaller than the length and diameter of the desired filament-wound reinforced nickel metal casing, to form a layer of separating material;   (b) coating the layer of separating material with a layer of a non-conductive insulating material;   (c) coating the layer of insulating material with a thin film of conductive metal;   (d) positioning the thus prepared mandrel horizontally in an electroplating bath provided with means for longitudinally rotating said mandrel at controlled speeds; and wherein said electroplating bath contains a nickel salt electrolyte solution at a depth whereby about 10 to 25% of the outer surface of the mandrel is not immersed but exposed;   (e) electrodepositing nickel metal on the thus prepared outer surface of the mandrel while the mandrel is being rotated through said electrolyte solution;   (f) winding carbon fiber filaments on the exposed outer surface of the mandrel as the mandrel is being rotated and while electrodepositing nickel from said electrolyte on to the outer surface of the mandrel to form a reinforced nickel metal casing having an internal insulation layer attached thereto; and   (g) separating said reinforced nickel metal casing from the mandrel by applying heat to said mandrel whereby the layer of separating material melts thereby permitting the reinforced nickel metal casing with the internally attached insulating layer to be separated from the mandrel.   
     
     
       11. The method of claim 10 wherein said mandrel is made of steel. 
     
     
       12. The method of claim 10 wherein the separating material is wax. 
     
     
       13. The method of claim 10 wherein the insulating material is rubber. 
     
     
       14. The method of claim 10 wherein the thin film of conductive metal is silver film. 
     
     
       15. A product formed by the method of claim 1. 
     
     
       16. A product formed by the method of claim 10.